Process for stabilizing the viscosity characteristics of coal derived materials and the stabilized materials obtained thereby

Abstract

A process is disclosed for stabilizing the viscosity of coal derived materials such as an SRC product by adding up to 5.0% by weight of a light volatile phenolic viscosity repressor. The viscosity will remain stabilized for a period of time of up to 4 months.

What is claimed is: 
     
       1. A process for stabilizing the viscosity during handling and storage at temperatures of 35°-150° C. for a period of time up to about four months of a homogeneous, single phrase blend of solvent refined coal and solvent refined coal liquid distillate which liquid distillate contains indigenous nitrogen base compounds, both derived via liquefaction of a coal feed stock, which process for viscosity stabilization comprises: (a) adding to said blend of solvent refined coal and solvent refined coal liquid distillate up to about 5.0 percent by weight of a light volatile phenolic viscosity repressor;   (b) passing said blend of solvent refined and solvent refined coal liquid distillate containing said light volatile phenolic viscosity repressor to a storage container while minimizing the loss of light volatile components present therein; and,   (c) maintaining a partial pressure of said phenolic viscosity repressor over said stored blend of solvent refined coal and solvent refined coal liquid distillate throughout storage of said blend to insure that said phenolic viscosity repressor attaches to nitrogen base compounds contained within said blend of solvent refined coal and solvent refined coal liquid distillate to negate a large increase in viscosity.   
     
     
       2. The process of claim 1 wherein the phenolic viscosity repressor is selected from the group consisting of phenol, alkyl substituted phenol wherein the alkyl radical has 1-5 carbon atoms and mixtures thereof. 
     
     
       3. The process of claim 1 wherein the phenolic viscosity repressor has a boiling point up to about 260° C. 
     
     
       4. The process of claim 1 wherein the phenolic viscosity repressor is a cresol. 
     
     
       5. The process of claim 1 wherein the phenolic viscosity repressor is a mixture comprising phenol and alkyl substituted phenols wherein the alkyl radical has 1-5 carbon atoms. 
     
     
       6. The process of claim 5 wherein the mixture is solvent refined coal and a light oil derived therefrom and the light volatile phenolic viscosity repressor is added in amounts up to about 2.0 percent by weight. 
     
     
       7. The process of claim 1 wherein the phenolic viscosity repressor has a boiling point within the range of 145°-260° C. and is added in amounts of 0.5-2.0 percent by weight. 
     
     
       8. The process of claim 1 wherein the loss of said volatile components is minimized by blanketing said blend of said solvent refined coal and said distillate oil with an inert atmosphere. 
     
     
       9. The process of claim 1 wherein the loss of volatile components is minimized by blanketing said blend of said solvent refined coal and said distillate oil with a water layer at a temperature of about 65° C. or lower. 
     
     
       10. The process of claim 1 wherein said water layer contains said phenolic viscosity repressor. 
     
     
       11. The process of claim 1 wherein said blend of said solvent refined coal and distillate oil are maintained at 35°-150° C. with minimal agitation. 
     
     
       12. The process of claim 1 wherein the partial pressure of said phenolic viscosity repressor is maintained in part by reflux condensation and reinjection of the condensate into the blend of said solvent refined coal and said distillate oil.